ref(global) move modules, extract constants

backend/api_server/src/init/server.rs

@@ -0,0 +1,52 @@
+use std::env;
+use std::error::Error;
+use std::num::ParseIntError;
+use std::process::exit;
+
+use crate::blog;
+use axum::Router;
+use constants::config::server::{default_value, var_name};
+use macros::panic_with_log;
+use sqlx::{Pool, Postgres};
+use tracing::{error, info, warn, Level};
+
+pub async fn start(db_pool: Pool<Postgres>) -> Result<(), Box<dyn Error>> {
+    let app = Router::new()
+        .nest("/blog", blog::get_router())
+        .with_state(db_pool);
+
+    let port: u32 = match env::var(var_name::PORT) {
+        Ok(value) => value.parse().unwrap_or_else(|e: ParseIntError| {
+            warn!(
+                "failed to parse `{}`, using default port: {}",
+                var_name::PORT,
+                e.to_string()
+            );
+            default_value::PORT
+        }),
+        Err(_) => default_value::PORT,
+    };
+
+    let listener =
+        match tokio::net::TcpListener::bind(format!("{}:{}", default_value::HOST, port)).await {
+            Ok(listener) => {
+                info!("server started on {}:{}", default_value::HOST, port);
+                listener
+            }
+            Err(e) => {
+                panic_with_log!(
+                    Level::ERROR,
+                    "failed to start server on {}:{}: {}",
+                    default_value::HOST,
+                    port,
+                    e.to_string()
+                );
+            }
+        };
+
+    axum::serve(listener, app).await.unwrap_or_else(|e| {
+        error!("failed to start axum: {}", e.to_string());
+        exit(1);
+    });
+    Ok(())
+}